Preserving of raw hides and skins



PRESERVING OF RAW HIDES AND SKINS Filed April 4, 1934 Fig.5

J)? 1/ en for flax flex)? Patented Aug. 6, 1935 1 U ITED STATE rnnsnavnvc on RAW nmns AND sxms Max Stern, Mannhelm-Fendenheim, Germany Application is -i1 4, 1934, Serial No. 718,920 In Germany January 20, 1932 16 clai s. (01. 149-4) This invention relates to improved methods and means for preserving hides and skins prior to their dressing and tanning. p

It has hitherto been customary to preserve hides which have been freshly skinned from the animals by means of a rock salt. The action of the salt is to prevent the drying of the hides rather than to act as a preservative. Owing to its hygroscopic character the salt spread on the hide prevents evaporation from the skin with the resulting brittleness and keeps the skin in its natural state of flexibility. The salts which operate in this manner must be used in very liberal quantities, stored in a dry place up to to the time of use and other precautions must be taken to preserve the required properties of the salt. Further, owing to their high specific weight, their transport is expensive. In the actual application of the salts to the surface of the hide, it is almost impossible to present the entire mass of the salt to every portion of the surface of the hide in the proper physical state, namely that in which the salt left the store room. Excess salt is therefore applied to ensure efficient preserving and this means an added and avoidable expense and furthermore produces an undesirable slime on the work benches and floor of the salting room. Another very serious drawback consists in the formation of red patches on the inner side of the hide and these result in a loosening and displacement of the fibre in the finished product. I

By means of this invention it is sought to avoid all these drawbacks and to attain certain other advantages. in an economical manner. Broadly,the invention consists in employing for the preservation of hides awaiting tanning and dressing a mixture of pulverized tanned leather and salt. The pulverized leather may be produced from-scrap leather. A rock salt or an ordinary cooking salt may be used. The invention may be carried out in practice in many different ways and the following examples may be taken as illustrative and not as exhaustive.

1. Rock salt of the consistency and granular form hitherto used for preserving hides awaiting dressing and tanning is mixed with an equal quantity of pulverized oak tanned leather and this mixture is spread in a dry thin layer and evenly over the inner side of the hide to bepreservered. The hide is stored in this state till it is required for further treatment and remains fresh and flexible.

2. Finely pulverized chrome leather is soaked j in water and the extract obtained is drawn. Q 1

with the preservative- This extract contains substances which have a. beneficial action in preserving the hide. When it is required to prepare a.- mixture for application to the hide, some of the pulverized leather is mixed with the extract and a similar quantity of salt is added whereby a paste isobtained. This is spread in a thin layer on the inner side of thehide'and the hide is then rolled or folded. When at a later stage it is desired to subject the hide to tanning processes, the preserving layer as described can be very readily washed off. This operation is much more pleasant and easier to perform than formerly owingto the relatively dry state of the hide. F u'ther the hide is found to soak much more rapidly the time required being about 1-2 days. V

3. Leather or leather scrap, rock salt and tobacco leaves all preferablyin the form of a fine powder are well mixed. The mixture may be in the following proportiontedits by weight Leather Rock salt g 3 Tobacco 1 To this mixture there may be added an aromatic carbon compound such as ;8. -l* {aphtol or naphthalin. The entire mixture'isa :greyish white powder.

4. Another met 7 consists in employing a carrier for. any of the mixtures describedin the above examples numbered 1-3 and applying this. carrier duly charged mixture to the surface of the hide to be treated. The carrier may be made of an oiled paper, textile fabric, sea-weed, cotton or wool waste or like material. The charging of the carrier may be effected by moistening the carrier and scattering the preservative mixture according to any of the Examples 1-3 over the surface. The carrier material may be strewn with the preservative powder to which an adhesive powder has been. added or the adhesive powder may be mixed with the carrier which is then moistened and the preservative mixture added. It is usually preferable to form the carrier as a flat sheet or web and to pass it after treatment with the adhesive, moisture and preservative, through two pressure rolls sothat there is effected an even distribution and firm fixing of the preservative over the entire surface of the carrier.

Another modification consists in subjecting the preservative or' the preservative mounted on a carrier as described, to asmoking operation and d of applying this invention a this smoking operation may be eflected very simply by hanging the carrier for some time in a cold or hot smoke. The carrier may have the preservative on one side only thereof and the effective side of the carrier is preferably laid on the inner side of the hide and the carrier and hide are then rolled or folded together.

The method of carrying the invention into effect according to Example 4 provides an excellently convenient and favourable form of applying the preservative as it is clean, economical and simple to apply. The work rooms and floors are kept much cleaner than hitherto. In regard to the question of saving of material, it was formerly usual to use about 7 kilograms of salt on an average sized skin, whilst in accordance with this invention about one third or even less of this quantity is found adequate. The preserving action is so penetrating that the preserved goods are found to be perfectly impervious.

The examples above given all involve the use of pulverized components such as rock salt which, although in a very much smaller degree than formerly, still involve an undesirable accumulation of liquid on and about the hide under preservation. It is however possible to go one step further and to cut out the use of a hygroscopic agent so that practically dry preservation of the raw hide is effected. This is effected in accordance with this invention by producing a glue solution from a raw hide which has been preserved by one or other of the above described methods and the solution thus obtained is sprayed well into the raw hide to be preserved.

This form of the invention may be carried out as follows:

- 5. The fresh hide is first of all bespread on its inner side with a dry mixture of pulverized leather and rock salt and allowed to stand for some time either in the open or stacked in a pile of hides all of which have been similarly treated. The time of storage may be from 2 to 4 weeks. The preserved hide or the hide impregnated with the preservative, either with or without the hair is then placed in a hot water bath, kept at 100 C. and allowed to stand in this bath for about 24 hours. To 100 kilograms of hide having the preservative on its inner side, about 200 kilograms of water are used. By this method there is produced a glue solution which is then preferably filtered and then mixed with a rock salt solution to which some nipagin is preferably added. To one part of glue solution about one tenth part of salt is added. On standing, the solution gelatinizes. When required for preserving purposes the gelatinized solution is heated to bring it to a liquid state and is then well sprayed on the inner side of' the hide, whereby the hide so treated may be stored for any desired length of time and still -be kept in a supple and flexible state. It will be understood that any suitable germicide may be added to the glue solution.

Instead of employing leathers which have been tanned by vegetable tanning agents or chrome leather as described above, a leather which has been tanned by any other agent maybe used with satisfactory results.

To make my invention more clear, I have annexed a drawing.

Fig. 1 shows the carrier of paper provided with a dry even layer b of pickle salt on one side of the carrier. Fig. 2 shows the same preserving device having the layer on both sides. 3 the pickle salt is introduced in a liquid state into According to Fig.

the pulp, from which the paper or carrier 0 is made afterwards.

What I claim is:

1. Method for preserving hides and skins prior to their dressing and tanning, consisting in using 5 pulverized tanned leather and rock salt and spreading this mixture in a dry layer and evenly over the inner side of the hide to be preserved.-

2. Method for preserving hides and skins prior to their dressing and tanning, consisting in using a mixture composed of about equal parts of a salt component and pulverized tanned leather and spreading this mixture in a dry layer and evenly over the inner side of the hide to be preserved.

3. Method for preserving hides and skins prior to their dressing and tanning, consisting in using a mixture of a salt component and pulverized tanned-leather, in moistening this mixture with an extract produced by soaking tanned leather and separating off the liquor, and in spreading the moistened mixture in a thin layer and evenly over the inner side of the hide to be preserved.

4. Method for preserving hides and skins prior to their dressing and tanning, consisting in using 25 a mixture of a salt component, pulverized tanned leather and tobacco and spreading the mixture in a dry layer and evenly over the inner side of the hide to be preserved.

5. A method for preserving hides and skins 30 prior to their dressing and tanning, consisting in using a" mixture of a salt component, pulverized tanned leather and an aromatic hydro-carbon compound, and spreading the mixture in a dry layer evenly over the inner surface of the hide to be preserved.

6. A process for preserving hides and skins prior to their dressing and tanning, consisting in using a compound of salt and pulverized leather, in applying this compound to the surface of a pliable carrier in the form of a thin layer and then laying the said carrier with its layer on the inner side of the hide to be preserved.

7. A process for preserving hides and skins prior to their dressing and tanning, consisting in using a compound of salt and pulverized leather, in applying this compound to the surfaces of a pliable carrier in the form of a thin layer and then laying the said carrier on the inner side of the hide to be preserved.

8. A process for preserving hides and skins prior to their dressing and tanning, consisting in using a compound of salt and pulverized leather, in introducing this compound in a liquid state into a paper pulp, forming from the latter a paper carrier and in laying the paper carrier on the inner side of the hide to be preserved.

9. In the process of preserving hides and skins prior to their dressing and tanning as claimed in claim 7 in combination with the carrier the use of a tobacco component.

10. In the process of preserving hides and skins prior to their dressing and tanning as claimed in claim 7 in combination with the carrier the use of an aromatic carbon compound.

11. A preservative for preserving hides and skins prior to their dressing and tanning, consisting of a pliable carrier and a compound of a salt component and pulverized tanned leather the named compound being carried by the carrier in a dry thin even layer.

12. A preservative for preserving hides and skins prior to their dressing and tanning, consisting of a paper carrier to which a compound 75 layer, having mlled to its lurhce I. .preaefllnl substance as a coa and th n mam coated curler on and in contact with the inner side of the hide tobe preserved.

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